A irradiation system with a charged particle beam (1) comprising: a charged particle beam generation unit configured to accelerate and extract a beam of charged particles； a scanning electromagnet configured to explore the accelerated charged particle beam； a beam irradiation device (5) configured to irradiate the beam of charged particles accelerated to a plurality of irradiation points set respectively for a plurality of layers that are formed by dividing an irradiation target in a direction of travel of the beam of charged particles ； wherein a part or all of the plurality of the irradiation points are divided into a plurality of partitions； the partitions being created by dividing the dose of an irradiation point in the plurality of beam irradiation sections； a beam radiation dose measurement instrument (59) configured to obtain a beam dose of charged particles to pass through the beam irradiation device (5)； and a beam position measuring instrument (58) configured to obtain one or both of the position and width of the beam of charged electromagnetic particles scanned by the scanning electromagnet during irradiation at the point of irradiation with the beam of charged particles with respect to a partition； characterized in that: the beam position measuring instrument (58) is adapted to start the calculation of one or both of the position and the width of the beam of charged particles for each irradiation point when a dose signal is emitted from the partition satisfied, to obtain a calculation result and to determine if the result obtained is within a permissible range, and after the determination of a partition has been completed, start the calculation of one or both of the position and width of the charged particle beam obtained for the next partition.Un sistema de irradiación con haz de partículas cargadas (1) que comprende: una unidad de generación de haz de partículas cargadas configurada para acelerar y extraer un haz de partículas cargadas； un electroimán
